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Quantum Theory of Fields and Properties of Quantum Systems
Issue:
Volume 7, Issue 4, July 2019
Pages:
93-100
Received:
27 April 2019
Accepted:
3 June 2019
Published:
4 July 2019
Abstract: Quantum theory of fields is the most general theory to date. It has an extremely wide field of application: - the physics of elementary particles and their interactions (summarized by the Standard Model); - the physics of the universe close to the Big Bang (primordial fluctuations from which the formation of the structure of the universe originates, evaporation of black holes, Hawking radiation); - the formalism of condensed matter physics, with applications such as superconductivity, superfluidity, phase transitions. Indeed, the quantum theory of fields has been successfully implemented in quantum systems, notably in research on fundamental state energy, elementary excitations spectrum, degeneracy parameters: long range order, Bogoliubov approximation, density matrix diagonalization,…, as well as the characteristics of these systems: movement equation, dynamics of the system,…. Three different quantum systems were concerned in this theoretical study: - a gas of identical atoms of spin zero confined into the trap; - electron gas of spin ½ into the metal; - and a gathering of identical ions of spin zero at high density confined into a radiofrequency linear Paul trap. The microscopic theory was used in the each case and the results obtained by the researchers are presented.
Abstract: Quantum theory of fields is the most general theory to date. It has an extremely wide field of application: - the physics of elementary particles and their interactions (summarized by the Standard Model); - the physics of the universe close to the Big Bang (primordial fluctuations from which the formation of the structure of the universe originates...
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A Broadband Millimeter-Wave Waveguide Power Divider with High Isolation
Hua Zhang,
Deng Yun Shao,
Yun Shao
Issue:
Volume 7, Issue 4, July 2019
Pages:
101-108
Received:
27 May 2019
Accepted:
16 July 2019
Published:
5 August 2019
Abstract: In this paper, an E-plane stepped-impedance transformer and Y-junction bifurcation are used to form a waveguide power divider with ceramic substrate loaded with thin film resistors. This structure is realized high isolation in V-band by inserting a ceramic substrate at the H-plane center of the Y-junction waveguide bifurcation, both sides of which loaded with thin film resistors. The waveguide power divider was fabricated with aluminium-50% silicon, and has characteristics of light weight, lower coefficient of thermal expansion, good thermal conductivity, and its properties are more compatible with those of ceramic substrate. The principle and design procedure are described in detail. A V-band E-plane waveguide power divider is designed, fabricated, and measured. The measured results show that insertion loss is less than 0.4dB in the frequency range of 50~60GHz, with typical isolation levels of 25dB between the two output ports and amplitude imbalance less than 0.19dB, phase imbalance less than 1.4°. The measured and simulated results show good amplitude, phase, and isolation characteristics validating the proposed power divider.
Abstract: In this paper, an E-plane stepped-impedance transformer and Y-junction bifurcation are used to form a waveguide power divider with ceramic substrate loaded with thin film resistors. This structure is realized high isolation in V-band by inserting a ceramic substrate at the H-plane center of the Y-junction waveguide bifurcation, both sides of which ...
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Study on the Influence of Radon Collector Parame
Shangting Jiang,
Jian Shan,
Hui Yang,
Jinglin Li,
Songsong Li,
Tao Guo
Issue:
Volume 7, Issue 4, July 2019
Pages:
109-117
Received:
22 July 2019
Accepted:
14 August 2019
Published:
2 September 2019
Abstract: Accurate measurement of radon exhalation rate of building materials plays an important role in controlling indoor radon concentration. In order to achieve rapid and accurate measurement of radon exhalation, the influence of the volume, base area and pumping flow rate of radon collector on radon exhalation rate was studied to optimize the measurement parameters of radon exhalation rate and improve the measurement efficiency of radon exhalation rate. The study has shown that the larger the volume of radon collector is, the longer the radon concentration equilibrium time will be when radon exhalation rate is measured with constant pumping flow rate and surface precipitation rate, while the influence of the volume of radon collector on the equilibrium radon concentration can be neglected, but there is a specific linear relationship between the equilibrium radon concentration and the base area of radon collector. When the radon exhalation rate is measured with constant volume and base area of radon collector, the higher the pumping flow rate is, the shorter the radon concentration equilibrium time is and the smaller the equilibrium radon concentration is. When the radon exhalation rate is 3.9Bq∙m-2∙s-1 in the experiment, the optimum volume of radon collector is 2.1×10-3m3, the optimum base area is 3.46×10-2m-2, and the optimum pumping flow rate is 1.349×10-5m3/s. The measurement parameters of the radon exhalation rate, such as the best volume and base area of radon collector and the pumping flow rate can be obtained for different radon exhalation rates through this optimization method.
Abstract: Accurate measurement of radon exhalation rate of building materials plays an important role in controlling indoor radon concentration. In order to achieve rapid and accurate measurement of radon exhalation, the influence of the volume, base area and pumping flow rate of radon collector on radon exhalation rate was studied to optimize the measuremen...
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